block: remove test ioscheduler

Signed-off-by: Dan Trifan <jimsth@gmail.com>
defconfig: switch to deadline as default ioscheduler

Signed-off-by: Dan Trifan <jimsth@gmail.com>
block: deadline: Optimize for non-rotational

Signed-off-by: Dan Trifan <jimsth@gmail.com>